The overall objective of this work is to isolate the protective antigen in ribosomal vaccines isolated from Streptococcus pyogenes and Salmonella typhimurium. Previous work has suggested that two protective antigens are present in the ribosomal vaccine isolated from S. pyogenes; one responsible for protection against challenge with homologous M types and one responsible for protection against challenge with heterologous M types. Preparative flat bed isoelectric focusing will be used to attempt to separate these two antigens. Studies are also in progress to determine if the ribosomal vaccine isolated from S. pyogenes will protect against challenge with group B streptococci. The ribosomal vaccine isolated from Salmonella typhimurium has been shown to be contaminated with outer membrane proteins. In addition, the role of endotoxin protein has not yet been fully elucidated. The object of the proposed research is to complete the isolation of purified outer membrane proteins and endotoxin protein and to determine the role that each of these may play in the immunity induced by salmonella ribosomal vaccines.